And 94% of people in England have either vaccine-acquired or infection-acquired antibodies to SARS-CoV-2.
Welcome to The Medical Republic’s COVID Catch-Up.
It’s the day’s covid-19 news in one convenient post. Email bianca@biancanogrady.com with any tips, comments or feedback.
23 August
- UK data suggests viral loads are just as high in vaccinated individuals as unvaccinated, and protection wanes faster with Pfizer.
- Only 6% of people in England don’t have antibodies against SARS-CoV-2.
- One-quarter of people at US basketball games still not wearing masks properly or at all, study finds.
- Covid deaths in current Australian outbreak are below levels seen in the second wave.
- Testing numbers compared to positive tests in NSW.
- Latest covid infection numbers from around Australia.
Breakthrough infections with Delta in fully vaccinated individuals show the same viral loads as infections in unvaccinated individuals, researchers have found.
The unpublished paper from Oxford University also suggests that the AstraZeneca vaccine offers slightly longer-lasting protection against the Delta variant.
The study prospectively tested 740,000 people – around half in the first Alpha wave of the pandemic and half in the latest Delta wave – regularly with RT-PCR on a preset schedule, regardless of symptoms or vaccination status.
This revealed that in the second wave, which was dominated by the Delta variant, peak viral loads in vaccinated individuals with breakthrough infections were similar to those seen in unvaccinated individuals. While peak viral loads do correlate with infectivity, the authors commented that it wasn’t yet clear if this translated into a similar risk of transmission from vaccinated as unvaccinated individuals.
“Nevertheless, there may be implications for any policies that assume a low risk of onward transmission from vaccinated individuals (e.g. relating to self-isolation, travel), despite vaccines both still protecting against infection, thereby still reducing transmission overall,” the authors wrote.
Researchers also calculated that the efficacy of the Pfizer vaccine declined by 22% every 30 days after the second dose of the vaccine, while the efficacy of the AstraZeneca vaccine declined by around 7% every 30 days after the second dose. The difference between the two vaccines was even more pronounced when it came to preventing symptomatic infection.
The study also showed that the vaccines offered even greater protection against breakthrough infection in individuals who had previously been infected with covid than in those who were infection naïve. For example, the AstraZeneca vaccine was 88% effective in those who had been infected with covid compared to 68% in those who hadn’t.
A staggering 94% of people in England have antibodies against SARS-CoV-2, either from infection or vaccination, according to new figures from the UK’s Office for National Statistics. Just over four out of five adults are now fully vaccinated, and 92% have had at least one dose of the vaccine.
Only three-quarters of those attending a sports match in the United States where masking was mandatory actually wore masks properly or at all, a study has found.
Researchers analysed mask use among more than 21,000 people attending five basketball games at a stadium that was limited to 22% capacity, according to a paper published in JAMA.
At the time of the games, vaccine had not yet been rolled out and there was a high level of community spread. Masks were required, there were regular announcements and signs encouraging mask wearing, and ushers attempted to enforce the regulation.
Despite this, only 74% of attendees wore masks correctly or at all during the games, with women significantly more likely to wear their mask properly than men.
“When vaccinations are not available or coverage is low, ensuring adherence to key transmission mitigation strategies such as mask wearing during mass events is critical during the current, and any future, pandemic,” the authors wrote.
While Australia has now smashed previous records for the highest number of new infections in a day, so far the daily numbers of deaths are tracking considerably lower than what was seen during the second wave of the pandemic.
And here’s how the test positivity rate is tracking in NSW compared to total number of tests:
Here are the latest covid-19 infection numbers from around Australia to 9pm Sunday:
National – 44,028 with 981 deaths
ACT – 245 (19)
NSW – 17,997 (824)
NT – 200 (0)
QLD – 1964 (0)
SA – 869 (0)
TAS – 235 (0)
VIC – 21,455 (66)
WA – 1063 (0)
